How to use KPI Visual to show Efficiency Over Time

Using sample data below, I've created a basic KPI visual to show how our actual data compares to our target. Since our target is dynamic, how can I show on my KPI how we have improved/worsened to how close we get to our target over the month-by-month time period. 

For Example in January our Actual is 4 but our target is 8, in February our actual is 1 but our target is 4, so I want to show that we are going the wrong way in our efficiency when you compare those two months.